The present invention relates to an elastomer-based connector sheet or, more particularly, to an elastomer-based connector sheet having high flexibility and suitable for use, for example, in electrically connecting terminals of a surface-mountable IC package and an electronic circuit board as in the inspection of IC packages with high resolution even when the arrangement pitch of the terminals is extremely fine.
It is usually practiced heretofore, when a surface-mountable IC package is to be electrically connected to an electronic circuit board, for example, for the inspection of IC packages, that the terminals of a surface-mountable IC package are directly connected to the respective terminals of the electronic circuit board by clamping or by soldering or, alternatively, an IC socket is used to connect an IC package and the circuit board.
Along with the remarkable trend in surface-mountable IC packages of recent years toward larger and larger number of the terminals and finer and finer arrangement pitch of the terminals, however, problems are caused in the above mentioned methods for connecting the terminals of a surface-mountable IC package and the terminals of the circuit board. When electrical connection is effected by clamping or by soldering, for example, the reliability in the electrical connection is low because of eventual deformation of the terminals or bridging between terminals by the solder alloy or incomplete soldering not to ensure electrical connection between terminals requiring extremely high skillfulness of the workers if not to mention possible secondary troubles such as damages on the surface-mountable IC package per se, severance of the terminals on the circuit board and so on.
When an IC socket is used for connection, an IC socket cannot be provided with so many pins at a so fine arrangement pitch as a matter of practice to comply with modern surface-mountable IC packages resulting in eventual break or bending of the terminals of the IC package not to ensure high efficiency and good reliability of the electric connection.